Method and apparatus for forming windows in blanks for envelopes and other articles



Ob 7, 1941- A. WINKLER ET Al. 2,257,829

METHOD AND APPARATUS FOR FORMING WINDOWS IN BLANKS FOR ENVELOPES AND OTHER ARTICLES Filed Dec. 7, 1937 3 Sheets-Sheet l /Oer' 2,257,82 9 s Fon yOct. 7, 1941. A. WINKLER ETAL.

METHOD -AND APARATUS FOR FORMING WINDOWS IN BLANK ENVELOPES AND OTHER ARTICLES Filed Dec. '7, 1937 3 Sheets-Sheet 2 /oer Oct. 7, 1941. A, wlNKLER ETAL 2,257,829

METHOD' AND APPARATUS FOR FORMING WINDOWS IN BLANKS FOR ENVELOPES AND OTHER ARTICLES Filed Dec. '7, 1937 3 Sheets-Sheet 3 Wg@ i Patented Oct. 7, 1941 METHOD AND APPARATUS FOR FORMING WINDOWS IN BLANKS FOR ENVELOPES AND OTHER ARTICLES Alfra Winkler and Max nnebler, Neuwied, Germany Application December 7, 1937, Serial No. 178,494 In Germany April 21, 1937 14 Claims.

This invention relates to a method and apparatus for forming windows in blanks intended for making envelopes, bags and similar articles, of the type in which a window of transparent material is applied to a window opening in the blank. The apparatus may comprise a unitary mechanism for receiving the blanks, cutting the window openings, applying the transparent patch or panel, and delivering the finished blank; or may be combined with means for printing upon one or both sides of the blank; or may be embodied in or combined with a machine for the manufacture of the envelopes, bags or other articles.

The improved apparatus is adapted for the application of transparent material that can be welded or attached to the blank by the application of heat, and either with or without the initial application of dry heat-sensitive adhesive, and also for the application of transparent material requiring the use of liquid paste for its attachment to the blanks.

It has been heretofore proposed to apply ordinary transparent paper to the window openings of such blanks, by pasting around the edges of the openings, and it has also been proposed to employ certain cellulose films as transparent patches or panels and to attach this material after a preparatory treatment with a dry adhesive, and'to cause the dry edges to be welded to the blanks by the application of heat in a pair of flat surfaces adapted to be closed one upon the otherwhile the blank is held stationary by suction means. This method of application comprising the use of a stamp or die is, of course, entirely unsuitable for high speed operation, and for large production, as the operation is necessarily slow and requires that each blank and transparent patch or panel be rst brought to rest and then held in position during the welding operation.

One object of the present invention is to provide an improved method and apparatus having means for conveying the blanks and means for welding the patches to the blanks while being so conveyed. A further object is to provide rotary means for conveying the transparent material to the moving blanks. A still further object is to provide heated means for separating the transparent patches from a continuous strip, and a still further object is to provide-means for continuously feeding the successive blanks and for feeding the transparent material and for welding or pasting the separated patches to the edges of openings in the blanks.

With these and other objects in view, the invention consists in the novel method and construction hereinafter described. illustrated in the accompanying drawings and particularly pointed out in the appended claims, it being understood that various changes in the method and in the form and construction and inv minor details may be made without departing from the spirit of the invention or sacrlilcing any of the advantages thereof.

In the drawings, Figs. 1 and Zarranged side by side according to the dot-and-dash linesshow a vertical, longitudinal section of one form of the apparatus.

Figs. 3 to 10 inclusive show an envelope blank at different successive steps in the process caa,-

ried out by theapparatus shown at Figs. 1 and Figs. 11 to 13 inclusive show three successive" steps in the welding of a window patch according to a modified form of the apparatus; and Fig. 14 is a detail view showing such modified form of apparatus.

Referring to Figs. 1 and 2 of the drawings, the, apparatus illustrated thereby receives the blanks already shaped, and comprises means for printing upon both sides of the blanks, means for cutting the window opening, means for attaching the transparent patch, and means for stacking the cut-out portions of the blanks and for stacking the finished blanks.

Referring particularly to Fig. 1, the blank stack 2 is supported upon a tablel I andis retained in proper position by adjustable stops 3 and 3'. In the stack 2 the blanks correspond to Fig. 3. The hollow receiving roller 4 operates in the manner fully described in Patent No. 1,939,193, having a small rotating internal suction roller 5 which seizes the lowermost blank of the stack by its front point or edge and bends its front part downwardly over the freely rotating roller 6 arranged at the highest edge of the stack table I, so that the front point or edge of the blank is introduced between the said roller 4 and a spring-pressed counter-roller 1. Between the two rollers 4 and 1 the blank is now positively' seized and is pulled from beneath the rest of the stack. By the round guides 8 the blank is conducted between the roller 4. and a second counter-roller v9 also pressed against it by spring action. The further course of the blank, described in detail hereinafter, through the entire apparatus is indicated by means of dot-and-dash mes.

Passing from the rollers 4 and 9, the .blank is first seized by the roller l0 which, for that purpose, as is the case with a number of the other rollers and cylinders, is equipped with a suction channel s and with suction openings s' leading from such channel to the roller circumference. All these rollers vand cylinders which are provided with suction means are connected each toa suction air control device, not shown in the drawings, by which the suction air is controlled in proper timed relation to the operation of the apparatus. The roller III forms the printing/cylinder of a printing mechanism by means of which an inner imprint can be applied to the blank if so desired. Such inner imprint is indicated for example at Figs. 4 to 10 by the inner line a which runs substantially parallel to the outer contour line of the blank and is intended to indicate the marginal outline of this imprint. In the example shown the printing mechanism consists of a color trough II attached to a cross rail I2 extending between the two side frames G of the apparatus, a color dipper roll I3, a color applying roll I4, and a plate cylinder I5. The dipper and the applying rolls I3, I4 are jointly supported by a lever pair I3 which swings about an axle I1. Arms I3 secured on the cross rail I2 serve as a support for the axle I1, and the free ends of the two bearing levers I3 each rests with a stop screw I3 on one of the side frames G.

The printing cylinder I3 conveys the blank from the plate cylinder I5 to aA roller 23 which holds the blank by suction and is equipped with a hardened steel insert 2l. The blank passes between the rollery 2li and two rollers 22 and 23, the former of which is equipped in the known manner with two knives 24 for cutting out the two short window edges b (Fig. 5) running in the direction of travel of the blanks, and including the corner roundings adjoining their ends, while the second roller 23 carries two knives 25 for cutting out the two long window edges c (Fig. 6) lying crosswise of the direction of travel of the blanks. When the blank leaves the two rollers 23 and 23, therefore, the window opening d is completely cut out according to Fig. 7. I'he cut-out waste piece is held fast by suction upon the roller 23 through the medium of suction openings 25 located in the roller circumference between the two knives 25, and communicating with a suction channel 21 in the shaft. Each waste piece is taken over by the roller 23 which seizes it with its suction openings s' and adds it to a stack 33 resting on cross beams 29.

The blank with the window cut-out or opening therei n is passed on by the roller 23 to a cylinder 3I having a diameter twice as great as that of the said operating and conveying rollers, so that it takes over and transmits two blanks for each revolution. Accordingly the cylinder 3I is provided at two points in its circumference-diametrically opposed to each other-with suction openings s' and suction channels s communicating therewith. By this cylinder 3| the blank is conveyed from the roller 23 and is passed on to a. printing cylinder 32 of small diameter making one revolution for each blank. The printing cylinder 32 belongs to a printing mechanism which serves for producing a iirm name or other outer imprint upon the blanks. Such outer imprint is indicated in Figs. 7 to 10 by the rectangle e shown by dotted lines. This printing mechanism in the example shown comprises a color trough 33 mounted upon a cross rail 34 carried by the side frames G. To the said cross rail two arms 35 are secured for the support oi' an axle 33 upon which swings a lever pair 31 whereby a color dipper roll 33 and a color applying roll 33 are supported. The two levers 31 each have an arm which at its free end carries a stop screw 43 which is braced upon a cross rail 4I fastened between the two side frames G. 'I'he roller 42 forms the plate cylinder of this printing mechanism for the outer imprint.

The blank passes between the printing cylinder 32 and the plate cylinder 42 and is seized by a large cylinder 43 which conveys three blanks to one revolution and is provided accordingly at three uniformly distributed points of its circumference with suction openings s' and corresponding suction channels s.

The cylinder 43-see Fig. 2-conveys the blank to that part of the apparatus which serves for fastening the window patch to the window opening of the blank. The mode of operating 'of this part of the apparatus and the application of the individual elements embodied therein depends on the transparent material which is used for the window patches to be fastened to the blanks. This transparent material in the example shown is in each case taken from a strip 44 which is wound in a roll 45. This roll is carried by a shaft 45 rotating in open bearings in the side frames G. The strip 44 unrolling from the roll 45 passes over guide rollers 41 and 43 and between a roller pair 43 and 53 actuated in such a way that the strip unrolls intermittently to provide a patch for each blank.

When the material employed is of such a nature that it must be cut, the rollers 43, 53 are so operated that the free end of the strip 44, that is to say, the place at which a window patch was previously detached, is conveyed each time in advance of the cutting edges of the two cooperating shear blades 5I and 52 to the extent of the strip piece required for one window patch. By these blades a window patch is then separated from the strip of material. 'I'he ends of the upper sheer blade 5I are fastened to two parts 53 guided on a shaft 54 extending between the side frames G and passing through slots in said parts 53. Extending downwardly from each part 53 is a bolt member 53 and at its lower end each bolt 53 is guided in a part 51 and is pressed downwardly by a spring 53. In this manner the springs 53 effect the downward movement of the upper shear blade 5I. Its upward movement is effected by two cams 53 fastened to the shaft 54 and engaged by rollers 55 mounted on the parts 53. The lower sheer blade 52 is attached by its two ends to the parts 51.

When the material employed for the transparent patches-is such that heat may be used for melting oi! the individual pieces from the strip 44, the roller 33 is used for this melting oil' and the shears 5I, 52 are put out of commission. 'I'he roller 33 is equipped for this purpose with a rail 3| extending in its longitudinal direction. This rail is built into the roller and projects beyond the roller circumference only with a sharp knife-like edge. It is electrically heated by means of a suitable device 52 to a degree of heat necessary for melting ofi' the patch. 'I'he free end of the strip 44 in this case is led by the roller pair 43, 53, by the length required each time for one windowpatch through the narrow split between the two rollers 33 and 33 arranged in close but not contacting relation. 'I'he rail 3| of the roller 33 in passing the roller 33, however. bears so close against its circumference that it eii'ects the melting ofi.' of the window patch. The roller 33 is so adJusted that it seizes either a window patch cut off by the sheers I, 52 or a window patch melted of! by the heated rail 6| of the roller 60 at the moment of this cutting-ofi or melting-oil, the patch being seized by suction through the suction openings s communicating with the suction channel s and being fed to a blank in the manner hereinafter described.

The further treatment of the blanks which, as set forth above, have gone as far as the-cylinder 43 and have been taken over by it, likewise depends on the material used for the window patches which are to be fastened thereto. In the first place the apparatus is adapted to fasten to the blanks window patches that permit of the socalled welding on. Among these belong the window sheets of transparent papers or. of cellulose foll of the viscose group provided with a onesided coating which becomes adhesive due to the effect of heat, and acetate foils which do not require a coating but become adhesive in themselves by the effect of heat. The blank to be provided with a window patch of one of these kinds of materials is conveyed by the cylinder 43 to the roller 63 which feeds to the blank the window patch separated, in the manner above described, from the strip 44. The roller 63 is so adjusted that it lays the window patch upon the blank so as to cover the window opening d uniformly on all sides.

As the diameter of all the standard rollers making one revolution for each operation on the article is determined by the length of the largest blank to be handled in the apparatus, measured in its direction of travel, a minimum distance of these rollers may result which is too great for the continuous conveyance of the window patch fed towards them and lying upon the blank. For this reason the window patch f (Fig. 8), as soon as it has been laid upon the blank by the roller 63, is attached by this roller at spaced welded points g (Fig. 8) at the window edge lying in f ront in the direction of travel. This is effected by fingers 64 carried in the roller 63 and corresponding in number to the welding points, which fingers are electrically heated by a device 65 of any well-known kind. The fingers 64 are pivoted about a shaft 66 supported in the roller 63 and are controlled by a roll lever 61 likewise attached to the shaft 66 but outside of the roller and whose roll 68 engages a stationary cam 69. The control of the fingers 64 is so effected that with each revolution of the roller 63 they engage the leading edge of the window patch during a definite short movement of the blank and the window patch. In the circumference of the cylinder 43 inserts 43 of a low heat conducting material are fastened at those places where this point welding (and also the complete welding on of the window patches still to be described) is effected, in order to prevent a rapid drainage of the heat supplied to the window patch at the welding places.

The blank with the window patch f thus attached to it is conveyed by the cylinder 43 from the roller 63 to the roller 18 within which are carried-two rails 1I extending in its longitudinal direction and which are electrically heated by a suitable device 12. By these rails 1| the window sheet is welded to the blank alongside the two longitudinal window edges located crosswise of the direction of travel, as shown at Fig. 9 by the stippled portions. 'Ihe blanks then pass between the cylinder 43 and a roller 13 which, as in the example shown, may consist of individual parts attached to a common shaft, and comprising segments 14 adapted to be heated electrically by a suitable device 15,1and adapted to weld on the window patches along the two short window edges extending in the direction of travel in accordance with Fig. 10.

, The blank with the now completely welded-on window patch f is then conveyed by the cylinder 43 to a roller 16 and bythe latter to distributing or laying-ofi ydiscs 11, the blanks being seized by suction by both the roller 16 and the discs 11 by means of their suction openings s. The laying-o discs 11 in conformity with their greater diameter convey two blanks to one revolution and are therefore provided with two suction devices arranged diametrically opposite each other. The discs 11 release each blank when it is engaged by the cross beams 18 so that it then drops on to the stack 19. This stack rests on cross beams 88 which are adapted to swing downwardly automatically about the shaft 8l by automatic mechanism of a known kind as the stack increases.

A When the window material is of such a nature that it cannot be welded to the blanks but must be pasted the parts 64, 65; 1|, 12; 14, 15, which serve for the welding-on are all put out of commission. In this case the rollers 63, 18 and 13 which carry these said parts merely serve as conveying rollers. For pasting on the window patch there is provided, for the application of the adhesive around the window opening of the blank, a rotating segment 82 which cooperates `with the cylinder 43 and receives adhesive from a container 83 by means of a dipper roll 84 running in the same and of an applying roller 85. To the blank thus provided with an adhesive coating the window patch detached from the strip 44 by means of the shears 5l, 52 is fed by the roller 63 in the manner described andthe blank is conveyed to the stack 19 in the same manner as described above.

Referring to Figs. 11 to 14, the modified apparatus shown at Fig. 14 comprises three rollers 86, 1 3, 89, each having heated means for welding one or more edges of the transparent patch to the blank. In accordance with this apparatus the blank with the patch f thereon passes from the roller 63 to the roller 86 which latter has a longitudinal rail 88 heated electrically by a suitable device 81 and adapted to completely weld the patch edge previously attached to the blank only at the points g, (as in Fig. 8), so that the first or leading edge of the transparent patch is completely welded to one edge of the window opening, as shown at Fig. 11. By the action of the cylinder 43 the blank is then fed to the roller 13 which is provided with two, electrically heated rails or members 14 having suitable heating means 15 and adapted to engage the two parallel side edges of the patch extending in the direction of travel to weld such edges to the edges of the window opening as shown at Fig. 12. From the roller 13 the blank is fed by the cylinder 43 to the roller 89 which is provided with an electrically heated rail 9i having suitable heating means 90 and adapted to engage and Weld t0 the edge of the window opening the second cross edge, or trailing edge, of the transparent patch, so that all four edges of the patch are completely welded to the blank as shown at Fig. 13. From the roller 89 the blanks are fed by the cylinder 43 to the cylinder 16 in the manner above described in connection with Fig. 2.

Although the drawings and the above specification disclose the best mode in which we have circumstances require, without departing from the spirit of our invention within the scope of the appended claims.

What we claim is: 1. Method of forming windows in blanks intended for the manufacture of envelopes, bags, and similar articles which comprises conveying a strip of transparent material, conveying the blanks successively, applying heat to the said strip to separate' individual window patches therefrom by melting, applying a separated patch to each blank, and welding the edges of the patches to the edges of window openings in the blanks by the application of heated members to said edges.

2. Method of forming windows in blanks for the manufacture of envelopes, bags, and similar articles, which comprises feeding transparent patches to the blanks, applying heat at spaced points to connect the leading edge of each patch to a blank, then applying heat to said patch to .completely weld said edge to the blank, then applying heat to the trailing edge of the patch to completely weld said edge to the blank and finally applying heat to the patch edges extending in the direction of travel to complete the welding of the vpatch edges to the blank.

3. Apparatus for forming windows in blanks intended for the manufacture of envelopes, bags, and similar articles, comprising rotary members for conveying the blanks, means for applying transparent patches to the moving blanks, and two parallel and two arcuate members for progressively applying heat along definitely restricted lines conforming to the edges of the moving patches to weld the same to the blanks while the latter are advancing through the apparatus.

4. Apparatus for forming windows in blanks intended for the manufacture of envelopes, bags, and similar articles, comprising rotary members for conveying the blanks, means for applying transparent patches to the moving blanks, and rotary means including straight members and spaced arcuate members for applying heat progressively and to definitely restricted marginal edges of the moving patches to weld the same to the blanks without interrupting the forward movement of the blanks.

5. Apparatus for forming windows in blanks intended for the manufacture of envelopes, bags, andfsimilar articles, comprising rotary means for conveying the blanks successively and continuously, means for feeding a continuous strip of transparent material, means for separating patches from said strip, means for feeding the patches to the moving blanks, rotating means including spaced arcuate members for welding the advancing patches to the blanks by a rolling action and by the application of heat restricted to the edges of the patches and applied thereto progressively from edge to edge of the patch, and means for receiving the finished blanks.

6. Apparatus for forming windows in blanks intended for the manufacture of envelopes, bags, and similar articles, comprising rotary means for conveying the blanks successively and continuously, means for feeding a continuous strip of transparent material, means for separating patches from said strip, means for applying the patches to the moving blanks, rotating electrically heated members in the form of arcuate strips for progressively engaging and welding the edges of the patches to the blanks by the application of heat, the rotation of said members being uninterrupted during the welding, and means for receiving the finished blanks.

7. Apparatus for forming windows in blanks intended for the manufacture of envelopes, bags, and similar articles, comprising rotary means for continuously feeding the blanks, rotary members cooperating with said means, means for conveying transparent patches to the blanks, heated elements in the form of arcuate and straight strips carriedby said rotary members for engaging the patches to weld the same to the blanks with a rolling action while the blanks are advancing.

8. Apparatus for forming .windows in blanks intended for the manufacture of envelopes, bags, and similar articles, comprising rotary suction means for continuously feeding the blanks, rotary members cooperating with said means, means for intermittently conveying transparent Patches to the blanks, electrically heated elements in the form of spaced arcuate strips and spaced parallel strips carried by said members for engaging the marginal edges of the patches to weld the same to thev blanks without interruption ofthe forward movement of the blanks.

9. Apparatus for forming windows in blanks intended for the manufacture of envelopes, bags, and similar articles, comprising rotary means for continuously conveying the blanks, a plurality of rotary members cooperating with said means, means for continuously rotating said members, means for conveying transparent patches to the blanks, heated elements in one of said members for engaging and welding two opposed edges of the patches to the blanks, and heated elements in another of said members for engaging and welding the other two opposed edges of the patches to the blanks.

10. Apparatus for forming windows in blanks intended for the manufacture of envelopes, bags, and similar articles, comprising means for continuously conveying the blanks, two rotary members cooperating with said means, means for imparting to said members uninterrupted rotary motion, means for applying transparent patches to the blanks, t'wo parallel heated elements in one of said members for engaging and welding the longitudinal edges of the patches to the blanks, and two arcuate heated elements in the other of said members for engaging and welding the short edges of the patches to the blanks.

11. Apparatus for forming windows in blanks intended for the manufacture of envelopes, bags, and similar articles, comprising means for continuously conveying the blanks, a rotary member for supplying transparent patches to successive blanks, a heated and continuously rotating member for welding the leading edge of the patch to the blank, a second rotary member having two arcuate strips for engaging and welding two of the other edges of the patch to the blank, and a third rotary member for welding the fourth edge of the patch to the blank.

12. Apparatus for forming windows in blanks intended for the manufacture of envelopes, bags, and similar articles, comprising means for continuously conveying the blanks, means for conveying a strip of transparent material, a heated member for separating the said strip into patches by melting, means for applying the patches to the blanks, and heating elements for welding the edges of the patches to the blanks.

13. Apparatus for forming windows in blanks f intended for the manufacture of envelopes, bags,

and similar articles, comprising means for continuously conveying the blanks, means for conveying a strip of transparent material, an electrically heated rotating member for separating the strip into patches by melting, means for applying the patches to the blanks, a plurality of rotary members engaging the patches upon the blanks, and electrically heated elements in said members for welding the edges oi the patches to the blanks by the application of heat thereto.

14. Apparatus for forming windows in blanks intended for the manufacture of envelopes, bags,

travel of the blanks.

um WINKLER. MAX DNNEBIER. 

